The invention relates to agricultural seeders, such as hoe openers and seeding tools used in farming operations to distribute seeds into a soil.
Generally, precision hoe openers are mounted to the frame of an implement which is towed behind a tractor. These openers may include an ground engaging tool that opens the soil, providing a path for seed deposition into the soil. The ground engaging tool is used to break the soil to enable seed deposition. After the seed is deposited, the ground engaging tool may be followed by a packer wheel that packs the soil on top of the deposited seed. The packer wheel may be rigidly mounted behind the opener via a structural member or rear frame. Thus, the ground engaging tool and packer wheel generally move together with the same upward and downward motion. This vertical motion, somewhat independent of the implement frame, allows for more precise placement of seed in the soil.
Unfortunately, existing precision hoe openers do not adequately address the need for height variation over terrain during seeding, or for transportation when not seeding. It is generally undesirable to pull the hoe opener through soil when merely transporting the opener from one location to another. In addition, during seeding, existing openers do not provide adequate vertical motion of the opener and related assembly without compromising the load on the ground engaging tool and packer wheel. As a result, variations in the terrain can result in drastic changes in the packing force (e.g., normal force) of the packer wheel on the terrain being seeded by the opener and, also, the draft force of the terrain on the ground engaging tool. In turn, this variation in grounding opening force and packing force can result in non-uniform seeding depths and packing density in the terrain being seeded.
For instance, some existing openers may employ a parallel linkage to control the location of the packer wheel and ground engaging tool. One of the difficulties in using a parallel linkage is that the force at the packer wheel will fluctuate as the parallel linkage changes orientation relative to the direction of the application of the draft force applied to the ground engaging tool. Moreover, the factors discussed above cause inconsistent forces to be applied to the packer wheel, which leads to variations in seeding depth and quality.
There is a need, therefore, for improved arrangements in precision hoe openers that improve the accuracy of the seeding operation. There is a particular need for a precision hoe opener configuration that maintains substantially constant forces on the packing wheel to improve seeding depth, accuracy and quality.